NO-Meal Announcement in Automated Insulin Delivery (Open-source and Commercial) Systems (NOMAD)

August 6, 2026 updated by: Rémi Rabasa-Lhoret, Institut de Recherches Cliniques de Montreal

Automated insulin delivery (AID) systems are the current gold standard for the management of type 1 diabetes (T1D), improving glycemic control, reducing hypoglycemia, and decreasing treatment burden. Although both commercial AID (C-AID) and open-source AID (OS-AID) systems have demonstrated significant clinical benefits, direct randomized comparisons between these systems remain scarce. Moreover, an important limitation of currently available AID systems is their reliance on user-initiated meal announcements and carbohydrate counting, which remain major contributors to postprandial dysglycemia and treatment burden. While emerging evidence suggests that AID systems may partially compensate for missed meal announcements, their comparative performance under these challenging real-world conditions is unknown.

The NOMAD study is an international, multicenter, open-label, randomized, non-inferiority crossover trial designed to compare an open-source AID system with commercially available AID systems (including Tandem Control-IQ and Omnipod 5) in adults with type 1 diabetes currently using an open-source AID system. The study specifically evaluates glycemic outcomes following standardized unannounced meal challenges performed under free-living conditions.

A total of 33 participants will be enrolled and complete two 4-week intervention periods, each consisting of a 2-week run-in phase followed by a 2-week data collection phase, with crossover between treatment arms. Participants will continue using their own Dexcom G6 or Dexcom G7 continuous glucose monitoring system throughout the study.

The primary outcome is the percentage of time spent in the target glucose range (3.9-10.0 mmol/L) during the 4 hours following standardized unannounced meal challenges. Secondary outcomes include additional CGM metrics (time above and below range, glucose variability, mean glucose, and GMI), insulin delivery characteristics, and patient-reported outcomes evaluating treatment satisfaction, usability, and diabetes-related burden.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

AID systems have become the preferred treatment for T1D, improving glycemic control, reducing hypoglycemia, and decreasing treatment burden compared with conventional insulin therapy. Both C-AID and OS-AID systems have demonstrated substantial clinical benefits, including increased time in range and improved patient-reported outcomes. However, despite their growing adoption, few randomized controlled trials have directly compared these systems under standardized conditions.

One of the major remaining challenges for current AID systems is the management of meals. Most commercially available systems are hybrid closed-loop systems that require users to announce meals and estimate carbohydrate intake before eating. Inaccurate carbohydrate estimation, delayed boluses, or missed meal announcements are common in daily life and contribute substantially to postprandial hyperglycemia and overall treatment burden. Although AID algorithms can partially compensate for these situations through automated insulin adjustments, their effectiveness varies between systems and has not been directly compared under real-world conditions.

This study aims to compare the performance of open-source and commercial AID systems during standardized unannounced meal challenges performed under free-living conditions. Adults with T1D who are experienced users of an OS-AID system will participate in a randomized, open-label, crossover trial in which they will use both their usual OS-AID system and a commercially available AID system. Throughout the study, participants will use the same Dexcom continuous glucose monitoring system to ensure consistent glucose assessment across study periods.

The primary objective is to determine whether OS-AID is non-inferior to commercial AID for maintaining postprandial glucose control following unannounced meals, as measured by the percentage of time spent in the target glucose range during the 4 hours after meal initiation. Secondary objectives include comparing overall glycemic outcomes, glucose variability, insulin delivery characteristics, and patient-reported outcomes related to treatment satisfaction, diabetes burden, and usability. The study will also explore differences in insulin dosing behavior, including user-initiated boluses, between the two AID approaches.

By evaluating glycemic performance in a common real-world scenario where meal announcements are omitted, this study will provide evidence regarding the comparative effectiveness, safety, and user experience of open-source and commercial AID systems. The findings are expected to inform clinical decision-making, support individualized selection of AID systems, and contribute to the development of future automated insulin delivery technologies that further reduce the burden of diabetes self-management.

Study Type

Interventional

Enrollment (Estimated)

33

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Canada
    • Quebec
      • Montreal, Quebec, Canada, H2H 1Y8
        • Institut de recherches cliniques de Montreal
        • Contact:
        • Principal Investigator:
          • Rémi Rabasa-Lhoret, M.D. Ph.D

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Males and females ≥ 18 years old currently residing in Canada or the United States of America (USA)
  • Having a clinical diagnosis of T1D for at least one year (based on the investigator's judgment; C peptide level and antibody determinations are not needed.)
  • Having been on OS-AID therapy for at least 2 weeks and using a Dexcom G6 or G7 CGM.
  • If using an ultra-rapid acting insulin, be willing to switch to a rapid-acting insulin, as the former are not recommended in the C-AID systems used in the study (due to the risk of cannula or pod blockage).
  • Accepting that personal pump setting parameters will be collected by the research team. This access will be limited to the study period.

Exclusion Criteria:

  • Using regular insulin (Novolin ge Toronto or Humulin R) or U200 or U500 concentrated insulin (e.g. Humalog U200, Entuzity U500)
  • Participant-reported clinically significant nephropathy (eGFR < 25 ml/min/1.73m2, planned or on dialysis), neuropathy (e.g., known uncontrolled gastroparesis) or retinopathy (e.g., proliferative retinopathy with ongoing active treatment such as laser photocoagulation or planned surgery) as judged by the investigator
  • Recent (<3 months) acute macrovascular event (e.g., acute coronary syndrome or cardiac surgery)
  • Anticipated therapeutic change (including change of CGM sensor [other than Dexcom sensors] or AID system type, new antidiabetic drug initiation) between admission and end of the study
  • % of time spent out of automated mode exceeding 10% in last month's trial start
  • Anticipated need to use hydroxyurea during the study period (as it can interfere with CGM readings)
  • Pregnancy (ongoing or current attempt to become pregnant)
  • Breastfeeding
  • Plan to go abroad in a foreign country during the study period
  • Severe hypoglycemic episode within one month of screening
  • Severe hyperglycemic episode (including DKA) requiring hospitalization in the last 3 months
  • Current use of glucocorticoid medication (except low stable dose and inhaled steroids and stable adrenal insufficiency treatment e.g., Cortef®)
  • Current use of SGLT-2 inhibitors or GLP1 agonists or other antidiabetic agents (Metformin, DPP-4 inhibitors) unless at a stable dose for at least 3 months, without anticipated change during the study and appropriate ketone testing is performed (for iSGLT2 treatment).
  • Known or suspected allergies to study products (e.g., Dexcom adhesive)
  • Other serious medical illnesses likely to interfere with study participation or with the ability to complete the study by the judgment of the investigator
  • Anticipation of a significant change in exercise or diet regimen between admission and end of the study (i.e., starting or stopping an organized sport; planned significant diet change)
  • Anticipated radiologic examination at the time of study assessment incompatible with CGM wear (e.g., MRI)
  • In the opinion of the investigator, a participant who is unable or unwilling to observe the contraindications of the study device.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: OS-AID
Participants will use their own OS-AID system, including Loop, AndroidAPS, or OpenAPS, together with their usual compatible insulin pump and a Dexcom G6 or Dexcom G7 continuous glucose monitoring (CGM) system. During the data collection phase, participants will complete two standardized unannounced meal challenges under free-living conditions. CGM and insulin pump data will be collected throughout the intervention period.
Device: Open-Source Automated Insulin Delivery (OS-AID)
Participants will use their own OS-AID system, including Loop, AndroidAPS, or OpenAPS, in combination with a compatible insulin pump and Dexcom G6 or Dexcom G7 continuous glucose monitoring (CGM). These systems use open-source algorithms to automatically adjust insulin delivery based on real-time CGM data through adaptive basal insulin modulation and, depending on the platform, automated correction boluses. Participants will continue using their established OS-AID settings throughout the intervention period without software updates and will be asked to perform two unannounced meal-challenges.
Active Comparator: Commercial-AID
Participants will use a C-AID system compatible with Dexcom CGM, including Tandem t X2 with Control-IQ or Omnipod 5, depending on their device and study allocation. Participants will receive study-provided equipment and training. During the data collection phase, participants will complete two standardized unannounced meal challenges under free-living conditions. CGM and insulin pump data will be collected throughout the intervention period.
Device: Commercial Automated Insulin Delivery (C-AID)
Participants will use a commercially available hybrid closed-loop AID system compatible with Dexcom G6 or Dexcom G7 CGM. Depending on study allocation and participants' usual device, the commercial system will include Tandem t X2 with Control-IQ technology or Omnipod 5. Participants not already using a compatible commercial AID system will receive study equipment and standardized training before initiating the intervention. Commercial AID systems automatically adjust insulin delivery based on continuous glucose measurements using manufacturer-specific algorithms while continuing to recommend user-initiated meal announcements and boluses for optimal performance.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Percentage of time in target glucose range during the 4 hours following unannounced meal challenges
Time Frame: During the final 2 weeks of each 4-week intervention period (following the run-in phase).
Percentage of time with sensor glucose between 3.9 and 10.0 mmol/L (70-180 mg/dL) during the 4 hours following standardized unannounced meal challenges, measured using continuous glucose monitoring (CGM). Data will be analyzed at the meal level using all meal challenges completed during each intervention period.
During the final 2 weeks of each 4-week intervention period (following the run-in phase).

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time in tight range
Time Frame: Final 2 weeks of each intervention period.
Percentage of time with sensor glucose between 3.9 and 7.8 mmol/L (70-140 mg/dL), measured by CGM.
Final 2 weeks of each intervention period.
Time Above Range (>10 mmol/L)
Time Frame: Final 2 weeks of each intervention period.
Percentage of time with sensor glucose >10.0 mmol/L (>180 mg/dL), measured by CGM.
Final 2 weeks of each intervention period.
Time Above Range (>13.9 mmol/L)
Time Frame: Final 2 weeks of each intervention period.
Percentage of time with sensor glucose >13.9 mmol/L (>250 mg/dL), measured by CGM.
Final 2 weeks of each intervention period.
Mean Glucose
Time Frame: Final 2 weeks of each intervention period
Mean sensor glucose concentration (mmol/L) measured using CGM.
Final 2 weeks of each intervention period

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Institut de Recherches Cliniques de Montreal

Collaborators

University of Alberta
Stanford University

Investigators

  • Principal Investigator: Rémi Rabasa-Lhoret, M.D. Ph.D, IRCM

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2026

Primary Completion (Estimated)

September 1, 2029

Study Completion (Estimated)

December 31, 2029

Study Registration Dates

First Submitted

August 6, 2026

First Submitted That Met QC Criteria

August 6, 2026

First Posted (Actual)

August 11, 2026

Study Record Updates

Last Update Posted (Actual)

August 11, 2026

Last Update Submitted That Met QC Criteria

August 6, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NOMAD

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Due to ethical and regulatory constraints, individual participant data generated in this study will not be made available to other researchers. Study results will be made publicly available through peer-reviewed publications and sharing with people living with T1D and caregivers: webinar, Better website, etc.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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